Generating added value by Extrusion


Published on

Extrusion applied in the food processing industry serves for upgrading carbohydrate- and protein-based raw materials. In the field of carbohydrate-based raw materials, starch by far accounts for the largest share.

  • Be the first to comment

  • Be the first to like this

No Downloads
Total views
On SlideShare
From Embeds
Number of Embeds
Embeds 0
No embeds

No notes for slide

Generating added value by Extrusion

  1. 1. Digital Re-print - July | August 2012 Generating added value by Extrusion Grain & Feed Milling Technology is published six times a year by Perendale Publishers Ltd of the United Kingdom. All data is published in good faith, based on information received, and while every care is taken to prevent inaccuracies, the publishers accept no liability for any errors or omissions or for the consequences of action taken on the basis of information published. ©Copyright 2010 Perendale Publishers Ltd. All rights reserved. No part of this publication may be reproduced in any form or by any means without prior permission of the copyright owner. Printed by Perendale Publishers Ltd. ISSN: 1466-3872
  2. 2. FEATURE Generating added value by EXTRUSION by Christopher Rubin, Head of Product Management and Marketing, Pasta and Extruded Products business unit, Bühler, SwitzerlandE xtrusion applied in the food process- If the correct amount of thermal and ing industry serves for upgrading mechanical energy is introduced into the Bühler presents new carbohydrate- and protein-based product in the extrusion process, this will twin-screw extruderraw materials. In the field of carbohy- enable end products to be made which aredrate-based raw materials, starch by far soluble either in cold or hot water and have “The goal of our development effortsaccounts for the largest share. a certain bandwidth of viscosities. was to offer an extruder which would Swelling flours are used as binders, fill- satisfy customers’ needs in the respec- Grain-based foods are staples throughout ers, or freshness extenders in baked goods. tive segments they are engaged in whilethe world. Day in, day out, millions of tons The extrusion process is particularly suited still being a much simpler solution thanof grain are processed in food production to the modification of flours because it the comparable all-rounder PolyTwin,”plants. In addition to baking flour, dark flour does not require the use of any chemi- explains the development engineer inand bran are also obtained during grain cals whatever. These flours are therefore charge.processing, especially with wheat. suitable also as ingredients in products Extrusion technology is a possible way of subject to a ‘clean label policy’. When usingfurther processing flour and the by-products extruded swelling flours, it is enough toobtained in the process. Extruders are used declare wheat flour on the ingredient a wide variety of flour processing applica-tions. The most important resulting products Extrusion as an alternative The PrioTwin has been designed forare breakfast cereals, baby food, bread- Another possible use is the production of continuous production with few prod-crumbs, croutons, plus modified flours and breadcrumbs. Extrusion technology enables uct changes. Thanks to its new modulesstarches used, for example, as soup or sauce breadcrumbs to be produced on the basis and its leaner design, it is particularlybinders or in the bakery industry. of a wide variety of raw materials. Whereas easy to operate. It combines proven high-protein flours such as wheat or rye processes using simplified modules,Modified and still a clean label flours are needed for developing a gluten which reduces the capital investment Modified flours are also called swelling framework in the traditional production proc- cost. In developing this new design,flours. Swelling flours are characterised by ess, it is basically possible to apply all starch- careful attention was also paid to inte-their modified water absorption capacity and containing products in the extrusion process. grating the extrusion process optimallytheir solubility properties. The viscosity of This also allows the use of lower-grade wheat in the upstream and downstream proc-flour-and-water suspensions can be adjusted flours or corn (maize), rice, or potato flours. ess stages in order to offer integral solu-to the specific applications by selection of the In this case, the dough is caused to rise on tions with a high customer value.suitable extrusion parameters. the one hand due to its expansion at the die.16 | July - august 2012 Grain &feed millinG technoloGy
  3. 3. FEATURE Extruded Bran Sticks – a by-product transformed into flours as well as wheat bran are valuable food as a rule sold at low prices to the feed manufacturing industry. The extruder enables also such ‘by-products’ to be upgraded into high-grade foods. Both by-products can be processed into breakfast cereals, but are also used in a modified form as ingredients in other foods. Bran flakes are highly popular today. Extruded wheat bran, for instance, can fetch double the price of wheat bran in its native form. The opportunities that wheat bran presents as a high-grade food are significant. The high dietary fiber content of wheat bran gives the product an ‘aura of health’. The basis for making all the products mentioned above is grain flour. This is what the extru- sion process has in common with conventional bakery proc- esses. The difference however lies in the dough texture. The dough framework of conven- tional bakery goods is based on proteins such as gluten and pen- tosans. The texture of extruded products is based on starch. The raw material must have a starch content of at least five to ten percent in order to ensure a stable end product texture. The protein content may be low, that is, below ten percent. Flours with such protein contents are typi-On the other hand, dough rising can also be a capacity of two metric tons per hour – are cally unsuitable for baking. As the flour pricecontrolled through specific chemical or physical twice as high in the traditional process as in is – among other factors – also influenced byagents. Fluctuations in the raw material quality the extrusion process. In addition, the extruder the protein content, low-protein flours areare easier to balance in the extrusion process. offers the flexibility required to produce related less expensive than high-protein ones. TheIn addition, it is possible to accurately adjust the products such as baking peas and croutons or extruder therefore allows also inexpensivetexture, colour, and particle size. even bread chips on a given processing line by flours to be processed. Moreover, extrusion is a highly energy-effi- selecting an appropriate configuration.cient process. The much lower water contents More InforMatIon:in the product formula in comparison to tra- Extrusion increases value Christopher Rubin, Bühler AGditional production, in conjunction with short generation Tel: +41 71 9551111retention times, ensures low energy costs, Even very dark flours (low-grade flours) Fax: +41 71 9553851especially during subsequent drying. The energy and wheat bran are suitable as raw materials Email: christopher.rubin@buhlergroup.comcosts per ton of finished product – based on for processing by the extruder. Low-grade Website: www.buhlergroup.comGrain &feed millinG technoloGy July - august 2012 | 17
  4. 4. Innovative extrusion processes without limits. Bühler is the global technologypartner for companies producing breakfast cereals, snack foods, or food in-gredients on a commercial scale. With its extensive extrusion know-how andits passion for customized solutions, Bühler is always in a position to generateadded value and success for any product idea. Bühler offers an integral range ofproducts and services for all process stages – from correct raw material handling,cooking and shaping through extrusion to drying of the extruded products. Andthis for all market segments – from breakfast cereals and snack foods to modifiedflours and starches, texturized proteins, or vitaminized rice. In short: extrusionprocesses without, for a better world.
  5. 5. This digital Re-print is part of the July | August 2012 edition of Grain & Feed Milling Technology magazine. Content from the magazine is available to view free-of-charge, both as a full LINKS online magazine on our website, and as an archive of individual features on the docstoc website. Please click here to view our other publications on July - August 2012 • See the full issue • Nutritional impact of pellet binders • Visit the GFMT website • Contact the GFMT Team • A fresh perspective on UK milling wheat In this issue: • Generating added value by extrusion • Health • Technological & safety in • Subscribe to GFMT expertise the working Understand enzyme recovery environment in pelleted feed • Powder Containment A subscription magazine for the global flour & feed milling industries - first published in 1891 To purchase a paper copy of the magazine, or to subscribe to the paper edi- tion please contact our Circulation and Subscriptions Manager on the link adove. INFORMATION FOR ADVERTISERS - CLICK HERE Article reprints All Grain & Feed Milling Tecchnology feature articles can be re-printed as a 4 or 8 page booklets (these have been used as point of sale materials, promotional materials for shows and exhibitions etc). If you are interested in getting this article re-printed please contact the GFMT team for more informa- tion on - Tel: +44 1242 267707 - Email: or visit